The diode is the simplest semiconductor device, i.e. a single P-N connector. The diode conducts current only in one direction. This device has a low, ideally zero resistance in the direction of conduction, and a high, ideally infinite resistance in the direction of barrier. There are many diodes on the market (e.g. Schottki diode, Zener diode, rectifier diodes and rectifier bridges composed of them), which are characterized by various parameters that should be selected for a specific application. A diode bridge is a system of four (or more) diodes. This is a type of rectifier.